This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. 1. To examine the brain regions underlying each of two component processes of working memory assessed using FMRI when subjects are well-rested. 2. To examine the effects of 36-hours of TSD on cognitive performance associated with two component processes of working memory. 3. To examine the effects of 36-hours of TSD on brain regions underlying two processes of working memory as assessed with FMRI.